Double-pinion toothed gear-train.



WQ TREWHELLA. y DOUBLE PINION TOOTHBD GEAR TRAIN.

APPLIUATION FILED APR.14,1908.

940,091. Patented N0v.16,1909. l

' mental rack G as shown in Fig. 5.

UNITED STATES PATENT @FFCEQ WILLIAM TREWHELLA, OF TRENTHAM,VICTORIAAUSTRALIA, ASSIGNR T0 HIMSELF AND BENJAMIN TREWHELLAA, 0FTRENTHAM, AUSTRALIA.

DOUBLE-PINION TOOTHED GAPv-TRAN.

Specification of Letters Patent.

Patented Nov., 1d, i909.

Application led April 14, ISOt Serial No. 427,051.

To all 'whom it may concern.'

Be it known that I, WILLIAM TREWHELLA, a subject of the King of GreatBritain, residing at Trentham, in the State of Victoria, Commonwealth ofAustralia, have invented a Doublelinion r.toothed Gear-Train, of whichthe following is a specification.

This invention comprises a gear train in which the load is equallydivided between two sets of gears instead of one as isusual in suchmechanism as jacks, cranes and the like, and in which the movementimparted to the driven element is more uniform than is practicable whendriving by one gear only.

he invention comprises briefly a floating pinion engaging two pinionsgeared with a toothed element of any mechanism.

The following drawings comprise various adaptations of the invention.

Figure 1 is a partial front elevation of a device embodying myinvention. Figs. 2v

and 3 are respectively enlarged front. and vertical sectional views ot'another form of the gear, Fig. 4 an elevation illustrating theapplication of. the invention to a jack, and, Fig. 5 is diagrammaticview of a modi tieation. l

'According to this invention there are a pair 'of toothed operativepinions 1, 2, suitably journaled upon separate but parallel axles 3, 4,in a frame or casing 5 which gear either with a toothed element such asa straight rack 6 for lineal motion, or a seg- In the simplest form ofthis train of gear (Fig. 1) the two operating pinions 1, 2, are directlygeared with a loose or floating pinion 8, the axis 9 of which isnormally situated in the same plane with the axles 3,v 4, of theoperative pinions, but is free to move out of said plane when necessaryto coliform with slight differences in the relative angular velocitiesof said operating pinions. l@aid floating pinion may be rotated by anymeans such as by a pulley 10 or crank han die l1, and in order toprevent it moving endwise either it or the operative pinions or both maybe shrouded as shown. The pinions are preferably half shrouded so thatby the shrouds 14 rolling upon each other the .floating pinion ismaintained equidistant from the axes ot the wheels into which it iAgears. rihe. teeth on this pinion are preferably odd numbered so thatthe operative pinions engage with the toothed element-1n oppositephases, and .thus etfect a steady movement of toothed element to whichthe gear is applied.

Figs. 2 and 3 show a separate set of teeth or an additional toothedwheel 12, 13, each formed on or integral with the axles of the operativepinions and in such ease the ioating pinion 8 is geared therewith, bywhich construction a ditt'erent leverage'is obtained, but the sameobject is effected as in the si1nplcr form of this gear. In thisconstruction the floating pinion is preferably formed with. an evennumber of teeth and in order to compensate for the irregular angularvelocity of gears such as this having few teeth, the operative pinionsare spaced more or less than an `integral number of pitches apart as inFig. 3. lt will thus be apparent that the engagement of the teeth ot'one operative pinion occurs in the opposite phase to that of the other,and a steady movement of the toothed element is obtained.

Fig. 4 shows the application ofthe gear to a ack having a longitudinallysliding rack 6 mounted in the casing 5, and it will be noticed that thetoothed wheels l2, 13, formed integral with the axles of the operativepinions are duplicated and that two floating pinions 8, 8, are formedintegral on the same axle 9, the object of which is to obtain amoresteady and uniform motion though such lconstruction is not essential asthe forms of the gear shown in the other three tigures of the drawingsare equally applicable to this kind of jack, l

'lilith the foregoing construction a liner tooth pitch may be utilizedthan would be practicable were the whole load carried by one set ofgears.,

lt will be observed that instead of the floating pinion S being thedriving member of the gear train, the pinions l and 2 may alternativelybe the driving members in which case the pinion 8 would be the drivenmember.

Havin g now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed. l declare thatwhat l claim is gl. in a train ol gearing, a toothed element, a frametherefor, a pair of pinions having parallel axles journaled in the trameand gearing with saidelement, a toothed Wheel tast upon the axle ot eachpinion, a l floating pinion geared with said toothed Wheels and havingits axis normally in the plane of the axes of the first mentionedpinions but free to move out of said plane to conform with slightdifferences in the relative angular velocity of saidpinions, and meansto rotate said floating pinion.

2. In la train of gearing, a frame, a pair ofvpinions mounted onparallel axles :journaled in the frame, a longitudinal rack slidablymounted in the latter, a pair of toothed Wheels fixed on the axle ofeach pinion, and a pair of floating rotatable pinions in axial linegearing With said toothed 'wheels and arranged so that their axis isnormally in the same plane as the axes of said first inentioned pinionsbut free to move out of said plane to conform with slight differences inthe relative angular velocity of said pinions.

In testimony whereof I have hereunto set my hand inpresenee of twosubscribing witnesses.

VILLIAM TREXVHELLA. Yitnesses EDWARD NEEDIL-xu VATERS, VILLIAM GUESTHOLDEN.

